I'll also be posting some tips on how to prep cast iron for cooking {indoor use pans as well as dutch ovens!} and some information reading coals and how to use them to create various kinds of heat in later posts!
Over about half the coals, cook bacon until chewy. It will get crispy as it cooks with the potatoes.
Off of the coals, remove bacon from dutch oven and any excess grease, leaving about 2 tablespoons bacon fat in the bottom of the dutch oven.
Layer half of the sliced potatoes in the bottom of the dutch oven and sprinkle with half a teaspoon of season salt.
On top of the potatoes, layer half of the onion, half the jalapeno (if desired), half of the bacon, and then half of the cheese.
Repeat layers, using remaining ingredients and put the lid on the dutch oven.
For the Baking with Coals
With dutch oven on a stand or on a safe ground area, place 9 coals on the bottom and 18 coals on top. This should heat to about 375 degrees for a 12 inch shallow dutch oven.
Check periodically and adjust coals as necessary, adding more when the original coals begin to die down.
If the bottom of the potatoes are cooking too quickly even with coal adjustment, add 1/3 cup water to the bottom of the dutch oven.
The potatoes are finished when they are soft, this takes about 45 minutes.
For Baking in the Oven
Place in an oven that has been preheated to 400ºF.
Bake for 50-60 minutes, or until the potatoes are soft. You can check this by inserting a fork or butter knife into the center of the potatoes.
Notes
To make this recipe for a larger crowd, scale up the ingredients accordingly. A 12-inch dutch oven can hold 3 layers and still cook well, but use a larger dutch oven (or two 12-inch dutch ovens) for more than 12 potatoes.Additionally, this recipe can be scaled down. Use a smaller dutch oven to avoid burning any of the ingredients while cooking.